Enable BV proofs when using an eager bitblaster (#2733)

Enable BV proofs when using an eager bitblaster (#2733)

* Enable BV proofs when using and eager bitblaster

Specifically:
   * Removed assertions that blocked them.
   * Made sure that only bitvectors were stored in the BV const let-map
   * Prevented true/false from being bit-blasted by the eager bitblaster

Also:
   * uncommented "no-check-proofs" from relevant tests

* Option handler logic for BV proofs

BV eager proofs only work when minisat is the sat solver being used by
the BV theory.

Added logic to the --proof hanlder to  verify this or throw an option
exception.

* Bugfix for proof options handler

I forgot that proofEnabledBuild runs even if the --proof option is
negated. In my handler I now check that proofs are enabled.

* Clang-format